When a lawyer for the Mexican subsidiary of Wal-Mart Stores Inc. allegedly told executives at the retail giant’s Arkansas headquarters that managers across the border routinely resorted to bribery to avoid zoning, environmental and permitting regulations when building new stores, an internal investigation ensued.

But it was also shut down in 2006, even as investigators unearthed a wealth of information supporting the lawyer’s account, the New York Times (sub. req.) reported in a lengthy front-page article Tuesday. The newspaper says the Times pursued the investigation after Wal-Mart dropped it, documenting, among other information provided by former Wal-Mart attorney Sergio Cicero Zapata, that representatives in Mexico paid a $52,000 bribe to have a zoning map changed before it was published in a local newspaper and became official. As a result, the Times says, a new store was built where zoning prohibited the construction, despite public opposition.

An investigation is currently ongoing by the U.S. Department of Justice and the Securities and Exchange Commission, which are looking into whether Wal-Mart’s activities violated the Foreign Corrupt Practices Act, the Times reports. The newspaper says that based on its own extensive investigation, “Wal-Mart de Mexico was not the reluctant victim of a corrupt culture that insisted on bribes as the cost of doing business” but “an aggressive and creative corrupter” that “used bribes to subvert democratic governance.”

A Wal-Mart spokesman told the newspaper the retailer is “committed to having a strong and effective global anti-corruption program everywhere we operate and taking appropriate action for any instance of noncompliance.”